There are in existence now hundreds of thousands of cameras and lens shutters which have no provision for flash synchronization. In modern cameras, flash contacts are, of course, provided. In the older cameras and shutters, no provision was made and various expedients have been employed in order to synchronize the flash. My invention consists of using the sound or the vibration of the shutter or of other camera mechanisms to fire the flash.
Many camera shutters and many cameras are not provided with flash synchronization means. Hundreds of thousands of such cameras are still in existence and, particularly, many of them are used by professionals in the photographic business because of the excellence of the shutters and lenses involved.
In the past, there have been means to synchronize flash units with such shutters by using solenoids which were operated by the flash unit. In other words, the flash unit drove the shutter at the appropriate moment after the start of its flash. Such methods using solenoid synchronization do not work well, particularly with electronic flash units popular at the present time.
Many devices for controlling flash attachments for cameras are operated directly or indirectly by the push button or other mechanism which releases the shutter rather than by the vibrations created by shutter operation itself. Some of these devices have impact means, triggered by the shutter release button which strikes a piezo-electric element to cause it to generate an impulse voltage for operating the flash. See U.S. Pat. Nos. 3,528,354 and 3,726,195. All of these devices have a disadvantage in that they do not adequately synchronize the flash with the operation of the shutter. Moreover, it is difficult to apply the prior art devices to existing cameras.